Co-op Mode

First you need to enter the debug cheat at the press start screen, this is Up-C, Up, Left-C, Right, Down-C, Down, Right-C, R, A, B. Now start a multiplayer game with two or three players, not four. When you start use the spare pad to select a level and you will start a co-op game plus all the items will regenarate after a short amount of time.